Did you finance through them? Because if so, this seems similar to "yo-yo financing".
Seems like, if you did finance thru them, they will next say that your financing must change to a used financing, which would liely be higher APR.
If you financed thru them, that means their cut is likely bigger (someone correct me if i am wrong please).
Motive would have been to get u out the door on something agreeable to you. Then, bring u back after you have come to rely on the vehicle to get you more likely to the worse loan terms, which favor them.
Maybe its what they're up to, maybe not.
https://www.hg.org/auto-dealer-fraud.html